A Dual Side Electroluminescence Measurement System for LED Wafer Manufacturing
H.- T. Kim, J. Kim, S. Kim, H.- K. Yuh, D.- H. Kim, D.- H. Ahn and D.- S. ShinAffiliation:
Smart System Research Group, KITECH, 35-3, HongCheon, IpJang, CheonAn, ChungNam 331-825, Korea.
AbstractA measurement system is presented for evaluating the characteristics of both sides of an LED wafer using electroluminescence (EL). Integrating spheres (IS), photodiodes, pico-ammeters, spectrometers were installed in the front and rear sides to measure optical characteristics with minimum EL loss. A probe was connected to a source meter with a thin wire and attached using a transparent fixture in the front IS. The EL characteristics in a measuring point were peak wavelength, FWHM (full width at half maximum), forward current, forward voltage and reverse current. EL images were created by combining the motion of a stage and the EL characteristics. The correlation between the EL and the chip-level tests and the repeatability test showed that the dual measurement is useful for LED manufacturing. Our patents were applied to install the probe and create the EL image.
Electroluminescence, EL imaging, epi-wafer, Optical spectrum, LED manufacturing.
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